Calculate how many patio slabs you need for your patio or path. Enter the area and we round up to whole slabs, with 10% allowance for cuts and breakages.
Popular 600×600mm slabs cover 0.36m² each — roughly 3 per square metre. Sub-base, sand and mortar are separate; our sand calculator works out the bedding layer.
01 — The Calculator
Pick a material, pace out your plot, and the value engine prices every way to fill it — hippo bags, dumpy bags or handy sacks.
Enter dimensions to calculate.
Area
0.0 m²
600×600 slabs
0 approx
Wastage
+10%
Patio packs
0 × 15.25m²
Best price
—
Enter your plot size below — we'll price the cheapest way to cover it.
Worked example: 12m² patio
12m² ÷ 0.36m² = 33.3, plus 10% wastage = 37 slabs of 600×600mm. The calculator checks every slab size in the catalogue and prices the best value option.
A standard 600×600mm slab covers 0.36m², about 2.8 slabs per square metre — but always add 10% for cuts and breakages, and 15% for a mixed-size pattern. Slabs must go on a full mortar bed (4:1 sharp sand to cement) over 100mm of compacted MOT Type 1; spot-dabbing five blobs of mortar is the single biggest cause of rocking, cracked slabs. Build in a fall of about 1:60 (17mm per metre) so rainwater runs away from the house.
Porcelain needs a slurry primer painted on the back of every slab or it won't bond — skip it and the slabs lift within a couple of winters. Natural stone varies in thickness, so order from one batch and bed each slab individually. Plan the layout from the house outward so cut edges land at the borders, not in the main view, and leave pointing until the mortar has cured for at least 48 hours.
Each covers 0.36m², so 2.8 per m² — round up and add 10% for cuts.
Last reviewed: October 2026 · Reviewed by the Garden Calculator editorial team.
Garden Calculator — Project
My garden project · 26 October 2026
| Item | Qty | Each | Total |
|---|---|---|---|
| Estimated total | £0.00 | ||
Prices from the Garden Calculator sample trade catalogue — confirm with your merchant before ordering.